Indicating instrument for vehicle

ABSTRACT

A straight cold cathode fluorescent lamp is detachably held at the back of a dial plate by a plurality of fork-shaped holders to illuminate a plurality of scales formed on the front surface of the dial plate and accommodated in the reflector which is also detachably fixed to a casing of the indicator instrument. A circuit board is also detachably fixed to the reflector.

This is a division of application Ser. No. 08/859,099, filed May 20,1997 U.S. Pat. No. 5,964,515.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an indicating instrument for varioususes and, particularly, a vehicular indicating instrument having a lightsource such as a cold cathode fluorescent lamp driven by high voltagepower.

2. Description of the Related Art

JPB2-7-107490 discloses an indicating instrument which has a circularcold cathode fluorescent lamp for illuminating a dial plate andindicators. Because the cold cathode fluorescent lamp is circular, it isnecessary to provide various types and sizes of cathode fluorescentlamps for a plurality of types of indicating instruments.

SUMMARY OF THE INVENTION

The present invention has an object of providing an improved indicatinginstrument which has a simple structure and can be used for varioustypes of vehicles.

For this object, an indicating instrument for a vehicle has a generallystraight lamp extending in the longitudinal direction of the dial plate,a light conducting plate disposed on the back surface of the dial plate,and a reflector for accommodating the light source and reflecting lightof the light source to the light conducting plate.

Another object of the present invention is to provide an indicatinginstrument having a lamp which is easily replaced.

For this object, an indicating instrument has, in addition to the abovestructure, means detachably fixed to the casing of the indicatorinstrument to combine the light source and the reflector. Preferably, acircuit board is detachably fixed to the reflector.

In addition to the above feature, an indicating instrument preferablyhas a detachable connector, which has a terminal plate connecting thelight source to a high-voltage source and other terminal plates, and theterminal plate is disposed at a distance large enough to insulate itfrom other terminals.

Another object of the present invention is to provide an indicatinginstrument wherein the light source can be removed by an action in thelongitudinal direction of the casing.

For this object, a fixing member is fixed to the casing for detachablyholding the reflector in the longitudinal direction and an opening isformed in the casing so that the reflector and light source can passthrough the opening when they are removed from the casing in thelongitudinal direction.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and characteristics of the present invention aswell as the functions of related parts of the present invention willbecome clear from a study of the following detailed description, theappended claims and the drawings. In the drawings:

FIG. 1 is a front view of an indicating instrument according to a firstembodiment of the present invention;

FIG. 2 is a cross-sectional view taken along a line II—II of FIG. 1;

FIG. 3 is a front view illustrating a main portion of a connector of anindicating instrument according to the first embodiment viewed from adirection indicated by an arrow A of FIG. 2;

FIG. 4 is a cross-sectional view illustrating the connector taken alonga line IV—IV of FIG. 3;

FIG. 5 is an exploded view of a lamp unit shown in FIG. 1;

FIG. 6 is a circuit diagram of the indicating instrument according toembodiments of the present invention;

FIG. 7 is a main part of a variation of the lamp unit shown in FIG. 5;

FIG. 8 is a front view illustrating an indicating instrument accordingto a second embodiment of the present invention;

FIG. 9 is a cross-sectional view of a main portion of the indicatinginstrument taken along a line IX—IX of FIG. 8;

FIG. 10 is an exploded view of a lamp unit of the indicating instrumentaccording to the second embodiment;

FIG. 11 is a front view illustrating a main portion of a variation ofthe connector of an indicating instrument according to the embodimentsof the present invention;

FIG. 12 is a front view of the connector shown in FIG. 11 in thedisconnected state;

FIG. 13 is a cross-sectional view illustrating the connector taken alonga line XIII—XIII of FIG. 11;

FIG. 14 is a cross-sectional view illustrating a main portion of anindicating instrument according to a third embodiment of the presentinvention;

FIGS. 15A and 15B are cross-sectional views illustrating a lamp unitincluding a lamp, a reflector and a circuit board;

FIG. 16 is a cross-sectional view illustrating a main portion of anindicating instrument according to a fourth embodiment of the presentinvention;

FIG. 17 is a front view of the main portion illustrated in FIG. 16viewed from a portion indicated by an arrow B in FIG. 16;

FIG. 18 is a side view illustrating a variation of a hold member;

FIGS. 19A and 19B are a side view and a front view illustrating anothervariation of the hold member;

FIGS. 20A and 20B are cross-sectional views illustrating a lamp unitincluding a lamp and a reflector according to a fifth embodiment of thepresent invention;

FIG. 21 is a variation of a casing of the indicating instrumentaccording to the embodiments of the present invention;

FIG. 22 is a perspective view illustrating another variation of thecasing; and

FIGS. 23A, 23B and 23C are perspective and cross-sectional viewsillustrating other variations of the casing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(First Embodiment)

An indicating instrument 10 according to a first embodiment is describedwith reference to FIGS. 1-6.

As shown in FIGS. 1 and 2, the indicating instrument 10 is composed of adial plate 10 a, a straight cold cathode fluorescent lamp 10 b, a lightconducting plate 10 c, a light reflector 10 d which an L-shapedcross-section, a circuit board 70, a connector 80 and a circuit board90.

The dial plate 10 a has a black surface on which scales 11, 12, 13 and14 of engine rotational speed (r.p.m.),vehicle speed (km/h), enginecoolant temperature (H, C) and fuel amount (F, E) in the fuel tank (F,E) are respectively formed in a well-known manner. The black surface issurrounded by an annular wall member 20 and covered by a transparentfront panel 30.

The lamp 10 b is disposed behind the dial plate 10 a in the longitudinaldirection of the dial plate 10 a at an upper portion(left in FIG. 2)thereof and detachably fixed to a wall 17 of the reflector 10 d by apair of cylindrical holders 16 and a pair of forked clamps 17 a as shownin FIGS. 1 and 5. The lamp 10 b is long enough to illuminate all thescales 11-14 and lamp 10 b is provided with a heat wire H wound on thesurface thereof over the full length of the lamp 10 b as shown in FIG. 5and electrically connected as shown in FIG. 6.

The light conducting plate 10 c is made of an acrylic resin and fixed tothe back of the dial plate 10 a under the lamp 10 b so that the lightincidence portion 15 thereof faces the lamp 10 b. The back of the lightconducting plate 10 c is frosted to diffuse light so that light cominginto the conducting plate 10 b from the light incidence portion 15 canbe diffused by the back of the light conducting plate 10 c and conductedto the scales 11, 12, 13 and 14 effectively.

The reflector 10 d is detachably fixed to the dial plate 10 a and acasing 60 to cover the lamp 10 b. As shown in FIG. 5, the reflector 10 dhas a plurality of claw members 17 b extending toward the circuit board70, a plurality of claw members 17 c extending in the direction oppositeto the circuit board 70 (toward the casing 60) and a side wall 18.

The scales 11, 12, 13 and 14 are equipped with indicators respectively,which are driven by driving units. An indicator 40 and a driving unit 50for the engine r.p.m. scale 11 are shown in FIG. 2.

The driving unit 50 is housed in the casing 60 and has a rotary shaft 51extending through a hole of the dial plate 10 a to the front thereof tosupport the indicator 40.

The casing 60 has a flange 61, which has a plurality of slits into whichthe claw members 17 c of the reflector 10 d are fitted as shown in FIG.2. At the same time, the side wall 18 of the reflector 10 d abutsagainst the back of the dial plate 10 a.

As shown in FIG. 5, the circuit board 70 has a plurality of openings 71receiving the claw members 17 b of the reflector 10 d so that thecircuit board 70 can be detachably fixed to the back of the reflector 10d. The circuit board 70 has a pair of terminals T1 and T2 connected tothe lamp 10 b, a pair of forked terminals 72 which hold the terminals H1and H2 in the arms thereof at the opposite ends of the circuit board 70to make an electrical connection and a connector portion 74 into which aconnector 80 (See FIG. 4) is inserted, as shown in FIG. 5. Thus, thelamp 10 b, reflector 10 d and circuit board 70 compose a lamp unit U.

When the lamp 10 b is going to be replaced due to a breakdown thereof,the lamp unit U is detached from the casing 60. Therefore, thereplacement of the lamp 10 b can be carried out very easily.

As shown in FIGS. 3 and 4, the connector 80 is composed of a case 81made of an insulating material and a terminal unit 82 inserted in thecase 81 and is disposed between both circuit boards 70 and 90.

As shown in FIGS. 3 and 6, the terminal unit 82 has a terminal plate 82a connected between the terminal 101 of a high-voltage-power generator100 and the terminal T1 of the circuit board 70 connected to the lamp 10b, and another terminal plate 82 b connected between the terminal 102 ofthe high-voltage-power generator 100 and the terminal T2 of the circuitboard 70 connected to the lamp 10 b.

As shown in FIGS. 3 and 4, the terminal unit is composed of a pluralityof terminal plates 82 a, 82 b, 82 c, 82 d and 82 e which are disposedrespectively in grooves 81 a, 81 d, 81 g, 81 h and 81 i formed in thecase 81 and soldered to respective terminals of the circuit board 70 and90. An interval of the terminal plates 82 a, 82 b and 82 c between eachother is three times as long as an interval of the terminal plates 82 c,82 d and 82 e between each other, because the terminal plates 81 a and82 b are connected to the terminals 101 and 102 of thehigh-voltage-power generator 100 to supply the high-voltage power to thelamp 10 a as shown in FIG. 6. The other terminal plates 82 c, 82 d and82 e are connected to the ignition switch IG and the driving unit 50respectively through the circuit boards 70 and 90.

The circuit board 90 is fixed to the back of the casing 60 in parallelwith the circuit board 70 by a plurality of bolts and has thehigh-voltage-power generator 100 thereon, which has the terminals 101and 102.

The high-voltage-power generator 100 is powered by a battery Ba throughan ignition switch IG and generates, across the terminals 101 and 102,electric power of a voltage between hundreds of volts and tens ofthousand volts at a frequency of tens of kilohertz.

A heater circuit 110 supplies the heater H with electric power accordingto a signal of temperature of the lamp 10 b sent from a thermistor 111when a normally-closed switch 120 made of a thermosensitive material isclosed, and the cold cathode fluorescent lamp 10 b illuminates the dialplate 10 a through the light conducting plate 10 c. The thermistor 111has a pair of lead terminals, which are soldered to the circuit board70. The terminals T1 and T2 of the lamp 10 b are also soldered to thecircuit board 70 at opposite sides thereof. As the heater H heats thelamp 10 b and temperature of the surface of the lamp 10 b exceeds acertain value which indicates a normal temperature condition, the switch120 is turned off.

The switch 120 is disposed in a space sealed by the dial plate 10 a,reflector 10 d, light conducting plate 10 c and the flange 61 of thecasing 60 in order to keep accurate switching performance.

A variation of the indicating instrument according to the firstembodiment is shown in FIG. 7. The circuit board 70 is omitted, and thecold cathode fluorescent lamp 10 b, the heater H and the thermistor 111are respectively connected to the terminal plates 82 of the connector 80by a plurality of lead wires L. The thermistor 111 is held by a holder16 a which is mounted on the middle of the lamp 10 b. Other portions arethe same in structure as the indicating instrument according to thefirst embodiment.

(Second Embodiment)

An indicating instrument according to a second embodiment is describedwith reference to FIGS. 8-10. The light conducting plate 10 c, reflector10 d, casing 60 and circuit board 70 in the first embodiment arereplaced with a light conducting plate 10 e, a casing 10 f, a reflector130 and a circuit board 140 respectively. Other portions having the samereference numeral as the first embodiment are substantially the same instructure and function, and therefore description is omitted.

The casing 10 f has a longitudinal conduit 19 for accommodating the lamp10 b, which faces the light conducting plate 10 e through an opening 19a which opens to the light incidence portion of the light conductingplate 10 e. The light incidence portion has a reflecting surface 19 bfacing the lamp 10 b on the back thereof. The lamp 10 b is secured bythe reflector 130; the circuit board 140 is detachably fixed to the backof the reflector 130; and the circuit board 90 is fastened to the casing10 f by screw bolts.

As shown in FIG. 10, the reflector 130 has a base plate 131, both a pairof forked members 132 and a plurality of claw members 135 disposed on asurface of the base plate 131 and a plurality of claw members 133 on theopposite surface. The forked member 132 holds the lamp 10 b by its ownresiliency at opposite ends thereof. The circuit board 140 has aplurality of openings 141 which receive the claw members 133 detachablyand a connector portion 142 disposed at a portion adjacent to thereflector 130. The terminals T1, T2 of the lamp 10 b, terminals H1, H2of the heater H and leads of both the thermistor 111 and the switch 120pass through the base plate 131 of the reflector 130 and are inserted inholes of solder lands and soldered thereto respectively.

The thermistor 111 is held in a groove of a holder 16 b separate from agroove holding the lamp 10 b. The thermistor 111 and switch 120 arehoused in compartments 134 a and 134 b of the reflector 130respectively. Thus, the lamp 10 b, reflector 130 and circuit board 140compose a detachable lamp unit Ub.

The connector 80 is connected to the connector portion 142 afterassembling of the lamp unit Ub. The reflector 130 is, thereafter, fixedto the casing 10 f by the claw members 135 fitted in slits of the casing(not shown) as described before.

If the lamp has to be replaced with a new one, the unit Ub is detachedfrom the casing 10 f. It is not necessary that the lamp 10 b is strictlystraight. The lamp 10 b can be a generally straight lamp of some othertype such as a xenon lamp. The reflector can be detachably fixed to thelight conducting plate or the dial plate also.

The heater H can control the brightness of the lamp by changing wirecolor or number of turns of the wire in places.

A variation of the connector 80 is described with reference to FIGS.11-13.

The connector 80 in the first embodiment is replaced with first andsecond connectors 180 and 190 in the third embodiment.

As shown in FIGS. 11 and 12, the first connector 180 is composed of apair of connector cases 181 a and 181 b made of insulating material anda plurality of terminal plates 182 a-182 e made of conducting material.

The connector case 181 a has a pair of fixing pins 181 c fitted intothrough holes 71 formed in the circuit board 70, and the connector case181 b is fixed to the circuit board 90 by a pin 92 or the like.

As shown in FIG. 13, each of the terminal plates 182 a-182 e ispress-fitted into one of holes 183 a and 183 b of the connector cases181 a and 181 b, and each of the lower ends of the terminal plates 182a-182 e is inserted into one of through holes 91 formed in the circuitboard 90 and soldered thereto.

As shown in FIG. 13, the second connector 190 is fixed to the uppersurface of the circuit board 70 and is composed of a case 191, upperportions of the terminal plates 182 a-182 e inserted in holes 191 aformed in the case 191 and a plurality of S-shaped spring terminals 192a-192 e (only 192 c is illustrated in FIG. 13) disposed in the case 191to bias against the terminal plates 182 a-182 e (the spring terminal 192c biases the terminal plate 182 c in FIG. 13) respectively.

The interval between adjacent ones of the terminal plates 182 a-182 c isthe same as the interval between adjacent ones of the terminal plates 82a-82 c of the connector 80 of the first embodiment, and the intervalbetween adjacent ones of the terminal plates 182 c-182 e is the same asthe interval between adjacent ones of the terminal plates 82 c-82 e ofthe first embodiment. The terminal plates 182 a and 182 b are connectedbetween the high-voltage power source 100 and the cold cathodefluorescent lamp 10 b as in the same manner shown in FIG. 6.

The interval of terminal plates 82 a-82 e and 182 a-182 e can be held byan adhesive tape instead of the connector cases 81, 181 a, 181 b and191.

(Third Embodiment)

An indicating instrument according to a third embodiment is describedwith reference to FIGS. 14, 15A and 15B. The circuit board 70 abuts thebottom surface of wing members 17 u and 17 v which are formed on theopposite sides of the wall 17 of the reflector 10 d to face the lamp 10b via the wall 17. The circuit board is fixed to the bottom surface ofthe light conducting plate 10 c by a plurality of screw bolts 70 b (FIG.14 shows only one screw bolt) via sleeves 70 a.

As shown in FIG. 15A, connectors 171 and 172 are fixed to the uppersurface of the circuit board 70 respectively by the left side of thewing members 17 u and 17 v.

The connector 171 is composed of a connector body 171 a and an L-shapedconnector terminal 171 b. The connector body 171 a is fixed to the uppersurface of the circuit board 70 and has an open space 171 d. TheL-shaped connector terminal 171 b passes through the circuit board 70and extends in the open space 171 d in parallel with the circuit board70. The connector pin 171 c is disposed to align with the connectorterminal 171 b and passes through the side wing 17 u so that theconnector pin 171 c can hold the connector terminal 171 b detachably.The terminal T2 of the lamp 10 b is connected to the connector pin 171 cthrough the wall of the reflector 17.

As shown in FIG. 15A, the open space 171 d of the connector body 17 a isdetachably fitted to a projecting portion 17 w of the wing member 17 u.

On the other hand, the connector 172 is composed of a connector body 172a and an L-shaped connector terminal 172 b. The connector body 172 a isfixed to the upper surface of the circuit board 70 and has an open space172 d. The L-shaped connector terminal 172 b passes through the circuitboard 70 and extends in the open space 172 d of the connector body 172 ain parallel with the circuit board 70. The connector pin 172 c isdisposed to align with the connector terminal 172 b and passes throughthe side wing 17 v so that the connector pin 172 c can hold theconnector terminal 172 b detachably. The terminal T1 of the lamp 10 b isconnected to the connector pin 172 c through the bottom wall 17 of thereflector 10 d. The open space 172 d is detachably fitted to aprojecting portion 17 x of the wing member 17 v.

The circuit board 70 has an engagement hole 73 near the right surface ofthe wing member 17 u as shown in FIG. 15B so that a hook 119 d of anL-shaped arm 119 c, which extends from a hold portion 119 of thereflector 10 d, engages the engagement hole 73. The hold portion 119 hastwo grip ends 119 a and 119 b extending toward an opening 61 a which isformed in the right wall of the casing 60. The two grip ends 119 a and119 b bend inward to swing the arm 119 c outward when they arecompressed by two fingers.

The opening 61 a has a size large enough to allow human fingers to passtherethrough.

One end of the connector 80 is connected to the connector terminals 171b and 172 b of the connectors 171 and 172 through the circuit board 70,and the other end of the connector 80 is connected to the circuit board90. The remaining structure is almost the same as the first embodiment.

When the lamp 10 b is to be removed, insert fingers into the opening 61a of the casing 60 and compress the grip ends 119 a and 119 b so thatthe hook 119 d of the L-shaped arm can disengage from the engagementhole 73 as shown in FIG. 15B. Then, pass the hold portion 119 throughthe opening 61 a and pull the grip ends 119 a and 119 b together withthe lamp 10 b and the reflector 10 d toward the outside of the opening61 a. As a result, the connector pins 171 c and 172 c and the projectingportions 17 w and 17 x are subsequently disengaged from the connectorterminals 171 b and 172 b and the open spaces 171 d and 172 drespectively, and finally the lamp 10 b and the reflector 10 d can bepulled out of the casing 60.

(Fourth Embodiment)

A fourth embodiment is described with reference to FIGS. 16 and 17.

A reflector 10 d is similar to that of the first embodiment, and a holdmember 200 is adopted in this embodiment.

As shown in FIG. 17, the hold member 200 is detachably fixed to theright side of the light conducting plate 10 c to hold the reflector 10d. The hold member 200 is composed of a plate member 201 made of anelastic resin and a leaf spring 202. The plate member 201 has twopressor plates 201 a extending over opposite surfaces of the lightconducting plate 10 c to hold the light conducting plate 10 c at theboth sides thereof (only one pressor plate 201 a is shown in FIG. 17). Agrip portion 201 b is formed at an upper portion of the hold member 200.

The leaf spring 202 has a convex surface facing the reflector 10 d sothat the hold member 200 pushes the reflector 10 d toward the left inFIG. 17 elastically against a left side wall of the circuit board 70,thereby holding the reflector 10 d. Other portions are substantially thesame as those of the third embodiment.

When the lamp 10 b is to be removed from the casing 60 through theopening 61 a, insert fingers into the casing 60 through the opening 61a, hold the grip portion 201 b by fingers to disengage the hold member200 from the light conducting plate 10 c, pull the reflector 10 dtogether with the circuit board 70 and the lamp 10 b through the opening61 a out of the casing 10.

A variation of the hold member 200 is shown in FIG. 18. The leaf spring202 is replaced with a rubber member 204.

Another variation of the hold member 200 is shown in FIGS. 19A and 19B.

This hold member 200′ is composed of a leaf spring 211 and a screw bolt212. A lower end of the leaf spring 211 is rotatably fixed to a sideportion of the light conducting plate 10 c by the screw bolt 212 tonormally press an end of the reflector 10 d as shown in FIG. 19A. Whenthe lamp 10 b and the reflector 10 d are to be removed, the leaf springis turned as shown in FIG. 19B.

(Fifth Embodiment)

A fifth embodiment of the present invention is described with referenceto FIGS. 20A and 20B. The reflector 10 d of the fourth embodiment isreplaced with a reflector 10 f in this embodiment.

The reflector 10 f has a U-shaped cross section and is fixed to thecircuit board 70 as shown in FIG. 20B. The reflector 10 f has a pair ofconnector terminals 219 e which extend inside the reflector 10 f todetachably connect the terminal T1 of the lamp and the terminal H1 ofthe heater respectively. A connector 220 has a cylindrical connectorbody 221 and a pair of latches 222 having hooks 222 a and extendinglongitudinally from the connector body 221. A pair of connectorterminals 223 extend in the connector body 221 from the bottom wallthereof.

When the connector body 221 is moved to the left side of the reflector10 f as shown in FIG. 20A, the latches 222 are inserted into engagementholes 219 f. At the same time a pair of connector terminals 223 aredetachably connected to the terminal T2 of the lamp 10 b and theterminal H2 of the heater H. In this embodiment, the connection strengthof the connector terminal 223 is set to be stronger than the connectionstrength of the connector terminals 219 e. The connector terminals 223are connected to the circuit board 70 by a connector 224 as shown inFIG. 20B.

Other portions are substantially the same as those of the fourthembodiment.

When the lamp 10 b and the reflector 10 f are to be removed, press bothlatches by fingers to disengage the hooks from the engagement holes 219f and pull the connector body 221 out of the casing 60 through theopening 61 a. The terminals T1 and H1 are removed from the connectorterminals 219 e first. After removing the connector 224 from the circuitboard 70, the lamp 10 b and the connector 220 are pulled out of thecasing 60 through the opening 61 a, and the connector terminals 223 areremoved from the terminals T2 and H2.

A variation of the above embodiment is shown in FIG. 21. A cover member60 a having a knob 62 is formed on the casing 60 to cover the opening 61a.

Another variation of the fifth embodiment is shown in FIG. 22. A filtermember 60 b is detachably disposed in a groove formed along the innerperiphery of the opening 61 a.

Other variations are shown in FIGS. 23A, 23B and 23C.

The opening 61 a of this embodiment is covered by an integrated covermember 60 c which is generally surrounded by V-shaped grooved portions63 as shown in FIG. 23A or grooved portions 65 as shown in FIG. 23B,which is a cross-sectional view cut along a line indicated by arrows 23Bin FIG. 23A. The integrated cover member 60 c can be formed by cuttingthe casing 60 except for connecting portions 66 as shown in FIG. 23C.The cover member 60 c shown in FIGS. 23A, 23B and 23C has a handle 64 sothat the cover member 60 c can be torn off along the grooved portions 63or 65 or at the connecting portions 66 by pulling the handle 64.

The covers and filter member described above are not only effective toprevent foreign particles from entering the interior of the case 60 butalso add a fine appearance of the case.

In the foregoing description of the present invention, the invention hasbeen disclosed with reference to specific embodiments thereof. It will,however, be evident that various modifications and changes may be madeto the specific embodiments of the present invention without departingfrom the broader spirit and scope of the invention as set forth in theappended claims. Accordingly, the description of the present inventionin this document is to be regarded in an illustrative, rather thanrestrictive, sense.

What is claimed is:
 1. An indicating instrument for a vehicle having abattery and an ignition switch comprising: a dial plate having anindicating gauge disposed on a front surface thereof; a battery-poweredhigh-voltage generator, connected to said battery through said ignitionswitch, for generating AC voltage much higher than a hundred volt at afrequency more than ten kilohertz; a terminal unit having a pair ofhigh-voltage terminal plates and a plurality of low-voltage terminalplates including terminal plates respectively connected to said ignitionswitch and an input terminal of said high voltage generator; and a coldcathode fluorescent lamp which is driven by said high-voltage generatorthrough said pair of high-voltage terminal plates and is disposed at theback of said dial plate for illuminating said dial plate; wherein eachof said pair of high-voltage terminal plates is spaced apart from theother and from said low voltage terminal plates by an interval muchlonger than an interval between two of said low voltage terminal plates.2. An indicating instrument as claimed in claim 1, wherein said intervalof said high-voltage terminal plates is as much as three times as aninterval between two of said low-voltage terminals.
 3. An indicatinginstrument as claimed in claim 1 further comprising: a light conductingplate disposed between said lamp and said dial plate, said lightconducting plate having a light incident surface facing said lamp, and areflector for reflecting light of said lamp to said light incidentsurface.